The pulvinar nucleus of the thalamus, because of its anatomical relations with associated cortex and tectum, is assumed to play a role in the utilization of visual information for orientation and in control and initiation of motor acts. In order to explore this hypothesis, preliminary neurophysiological experiments will be done on single neurons on this nucleus in behaving, head-restrained monkeys. Modality of input and behavioral contingencies of these neurons will be evaluated, and the receptive field properties of visually driven cells will be intensively studied under states of fixation at different relative positions to the animal and in association with eye movements.